California’s minimum wage would increase to $13 an hour, the highest in the nation, under a bill approved by the state Senate and sent to the Assembly.

The legislation by Mark Leno, a San Francisco Democrat, would phase in the increase to $11 next year, $12 in 2016 and $13 by 2017. After that, the state minimum wage would be adjusted annually for inflation.

The legislation comes amid debate across the U.S. about income inequality. Thirty-four states are considering increases to the minimum wage, according to the National Conference of State Legislatures. Efforts by President Barack Obama to raise the federal minimum wage of $7.25 an hour have stalled in Congress.

If the bill becomes law, it would trump a law signed by Democratic Governor Jerry Brown last year that raised the minimum wage to $10 an hour by 2016.

The bill, which the Senate approved 21-12, must pass the Assembly to reach Brown’s desk. Both chambers are controlled by Democrats.